The present invention relates to an improved height adjusting apparatus for a swivel chair.
Applicant discloses in U.S. Pat. No. 4,087,070, assigned to the assignee of this application, a swivel chair having height adjusting apparatus enabling the use of a non-keywayed screw. However, the nut member and the hand wheel for turning the nut member are integrally formed, thus requiring machining of the hand wheel to form the nut threads. Further, another machining operation is required to form another threaded hole in the hand wheel into which a set screw is positioned for engagement with the chair base to prevent displacement of the screw member from the chair base when the seat is lifted. A hand wheel and nut member with machined threads is costly, both in terms of the materials used and the production effort expended. It is thus the general object of the present invention to provide an improved height adjusting apparatus for a swivel chair which also eliminates the need for a keywayed main screw.
It is the object of the present invention to provide a height adjusting apparatus having novel means for preventing axial displacement of the screw member when the chair seat is lifted.
It is another object of the present invention to provide a height adjusting apparatus for a swivel chair having a detachable hand wheel for turning the nut member on the screw.